Model-independent constraints on the shape parameters of dilepton angular distributions

The coefficients determining the dilepton decay angular distribution of vector particles obey certain positivity constraints and a rotation-invariant identity. These relations are a direct consequence of the covariance properties of angular momentum eigenstates and are independent of the production mechanism. The Lam-Tung relation can be derived as a particular case, simply recognizing that the Drell-Yan dilepton is always produced transversely polarized with respect to one or more quantization axes. The dilepton angular distribution continues to be characterized by a frame-independent identity also when the Lam-Tung relation is violated. Moreover, the violation can be easily characterized by measuring a one-dimensional distribution depending on one shape coefficient.Comment: 7 page

Cartilha - palestra sobre ferrugem asiática da soja.

Esta palestra trata de aspectos da ferrugem asiática da soja: uma doença recente no Brasil e com alto potencial de dano.bitstream/item/56144/1/ID-26146.pd

Heavy-ion Physics at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC): Feasibility Studies for Quarkonium and Drell-Yan Production

We outline the case for heavy-ion-physics studies using the multi-TeV lead LHC beams in the fixed-target mode. After a brief contextual reminder, we detail the possible contributions of AFTER@LHC to heavy-ion physics with a specific emphasis on quarkonia. We then present performance simulations for a selection of observables. These show that $\Upsilon(nS)$, $J/\psi$ and $\psi(2S)$ production in heavy-ion collisions can be studied in new energy and rapidity domains with the LHCb and ALICE detectors. We also discuss the relevance to analyse the Drell-Yan pair production in asymmetric nucleus-nucleus collisions to study the factorisation of the nuclear modification of partonic densities and of further quarkonia to restore their status of golden probes of the quark-gluon plasma formation.Comment: 18 pages, 7 figure

Arl13b interferes with α-tubulin acetylation

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Plasmodium falciparum malaria, bilateral sixth cranial nerve palsy and delayed cerebellar ataxia

We describe the case of a 14-year-old Caucasian male, a resident in the Democratic Republic of the Congo, who was observed in Portugal with severe Plasmodium falciparum malaria with high-level parasitemia and severe thrombocytopenia. The course was complicated by bilateral sixth cranial nerve palsy during acute malaria, followed by the appearance of delayed cerebellar ataxia during the recovery phase. This occurred after successful treatment with quinine plus doxycycline over seven days. Different levels of thrombocytopenia and C-reactive protein were observed during both neurologic events in the presence of HRP-2 positive tests for Plasmodium falciparum antigen. The patient recovered completely after three months

First report of acute autochthonous hepatitis E in Portugal

Hepatitis E infection is usually a self-limiting disease. In industrialized countries, sporadic cases of acute hepatitis E virus (HEV) infections have been described; their number seems to be increasing in European countries. We report the first human case of autochthonous acute hepatitis E confirmed in Portugal. Patients with acute non-A-C hepatitis should be tested for HEV in Portugal and hepatitis E infection should be considered in the differential diagnosis of unexplained hepatitis cases

Determination of chi_c and chi_b polarizations from dilepton angular distributions in radiative decays

The angular distributions of the decay products in the successive decays chi_c (chi_b) to J/psi (Upsilon) gamma and J/psi (Upsilon) to l+l- are calculated as a function of the angular momentum composition of the decaying chi meson and of the multipole structure of the photon radiation, using a formalism independent of production mechanisms and polarization frames. The polarizations of the chi states produced in high energy collisions can be derived from the dilepton decay distributions of the daughter J/psi or Upsilon mesons, with a reduced dependence on the details of the photon reconstruction or simulation. Moreover, this method eliminates the dependence of the polarization measurement on the actual details of the multipole structure of the radiative transition. Problematic points in previous calculations of the chi_c decay angular distributions are identified and clarified.Comment: Submitted to Phys Rev